System and Method for Moving a Headrest for Whiplash Prevention

ABSTRACT

System and method for preventing whiplash injuries to an occupant, in particular, during rear impacts, includes a movable headrest associated with the seat and a system for positioning the headrest adjacent a head of the occupant in an impact involving the vehicle. This latter system includes an anticipatory crash sensor system arranged to produce an output signal when an external object is approaching a rear of the vehicle at a velocity above a predetermined velocity, a headrest movement system arranged to move the headrest and a sensor system arranged to determine when the headrest contacts or is proximate the occupant&#39;s head. Upon the determination of a pending rear impact between the object and the vehicle, the output signal is produced by the crash sensor system and the headrest is moved into a position in contact with or proximate the occupant&#39;s head as determined by the sensor system.

CROSS REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent application Ser. No.11/381,001 filed May 1, 2006 which is a divisional of U.S. patentapplication Ser. No. 10/733,957 filed Dec. 11, 2003, now U.S. Pat. No.7,243,945, which is:

1. a continuation-in-part (CIP) of U.S. patent application Ser. No.10/234,063, now U.S. Pat. No. 6,746,078, which is a CIP of U.S. patentapplication Ser. No. 09/613,925 filed Jul. 11, 2000, now U.S. Pat. No.6,805,404, which is a CIP of U.S. patent application Ser. No.08/992,525, filed Dec. 17, 1997, now U.S. Pat. No. 6,088,640; and

2. a CIP of U.S. patent application Ser. No. 09/613,925 filed Jul. 11,2000, now U.S. Pat. No. 6,805,404, which is a CIP of U.S. patentapplication Ser. No. 08/992,525, filed Dec. 17, 1997, now U.S. Pat. No.6,088,640.

This application is related to U.S. Pat. No. 5,694,320 and U.S. patentapplication Ser. No. 10/895,121 on the grounds that they include commonsubject matter.

FIELD OF THE INVENTION

The present invention relates generally to systems and methods formoving a headrest in a vehicle to prevent whiplash to an occupant.

BACKGROUND OF THE INVENTION

A detailed background of the invention is found in the parentapplication, U.S. patent application Ser. No. 10/733,957, incorporatedby reference herein. Section 14.10 is particularly relevant to thepresent invention.

The definitions set forth in section 15 of the Background of theInvention section of the '957 application are also incorporated byreference herein.

All of the patents, patent applications, technical papers and otherreferences referenced in the '957 application and herein areincorporated herein by reference in their entirety.

OBJECTS AND SUMMARY OF THE INVENTION

It is an object of this invention to determine the position of the rearof an occupant's head and to use that information to control theposition of the headrest.

It is another object of the present invention to provide new andimproved headrests for seats in a vehicle which offer protection for anoccupant in the event of a crash involving the vehicle.

It is another object of the present invention to provide new andimproved seats for vehicles which offer protection for an occupant inthe event of a crash involving the vehicle.

It is still another object of the present invention to provide new andimproved cushioning arrangements for vehicles and protection systemsincluding cushioning arrangements which provide protection for occupantsin the event of a crash involving the vehicle and/or in the event of acollision into the rear of the vehicle, i.e., a rear impact.

It is yet another object of the present invention to provide new andimproved vehicular systems which reduce whiplash injuries from rearimpacts of a vehicle by causing the headrest to be automaticallypositioned proximate to the occupant's head.

It is yet another object of the present invention to provide new andimproved vehicular systems to position a headrest proximate to the headof a vehicle occupant prior to a pending impact into the rear of avehicle.

It is yet another object of the present invention to provide a methodand arrangement for protecting an occupant in a vehicle during a crashinvolving the vehicle using an anticipatory sensor system and acushioning arrangement including a fluid-containing bag which is broughtcloser toward the occupant or ideally in contact with the occupant priorto or coincident with the crash. The bag would then conform to theportion of the occupant with which it is in contact.

It is yet another object of the present invention to provide anautomatically adjusting system which conforms to the head and neckgeometry of an occupant regardless of the occupant's particularmorphology to properly support both the head and neck.

In order to achieve some of these objects, a motor vehicle including apassenger compartment and a system in accordance with the inventionincludes a seat on which an occupant sits, a movable headrest associatedwith the seat and a system for positioning the headrest adjacent a headof the occupant in an impact involving the vehicle. This latter systemincludes an anticipatory crash sensor system arranged to produce anoutput signal when an external object is approaching a rear of thevehicle at a velocity above a predetermined velocity, a headrestmovement system arranged to move the headrest and a sensor systemarranged to determine when the headrest contacts or is proximate theoccupant's head. Upon the determination of a pending rear impact betweenthe external object and the vehicle, the output signal is produced bythe crash sensor system and the headrest is then moved into a positionin contact with or proximate the occupant's head as determined by thesensor system prior to the impact of the occupant's head with theheadrest.

The headrest movement system may be arranged to move the headrest froman initial position to a position proximate to the occupant's head, andthe sensor system may be arranged to determine the location of theoccupant's head relative to the headrest. A processor determines themotion required of the headrest to place the headrest proximate theoccupant's head and provides the motion determination to the headrestmovement system upon receipt of the output signal from the crash sensorsystem. Upon the determination of a pending rear impact between theexternal object and the vehicle, the output signal is produced by thecrash sensor system and the headrest is then moved into a positionadjacent the occupant's head prior to the impact of the occupant's headwith the headrest. The sensor system may include a transmitter attachedto the headrest for transmitting radiation to illuminate differentportions of the occupant's head, one or more receivers attached to theheadrest for receiving a set of first signals representative ofradiation reflected from different portions of the occupant's head andproviding a set of second signals representative of the distances fromthe headrest to the nearest illuminated portion of the occupant's headand a computational system for determining the headrest verticallocation corresponding to the nearest part of the occupant's head to theheadrest from the set of second signals from the receiver(s).

The sensor system may be operable in the presence of objects whichobscure the occupant's head. In this case, the sensor system may includea transmitter for illuminating a selective portion of the occupant andthe head-obscuring objects in the vicinity of the occupant's head, anillumination sensor system for receiving illumination reflected from theoccupant and the head-obscuring objects and providing a signalrepresentative of the distance from the illumination sensor system tothe illuminated portion of the occupant and the head-obscuring objects,a system for changing the selective portion of the occupant and thehead-obscuring objects which is illuminated by the illumination, and aprocessor including an algorithm for sequentially operating theselective portion changing system so as to illuminate different portionsof the occupant and the head-obscuring objects to thereby obtain aplurality of distance measurements from the illumination sensor systemto the different portions of the occupant. A pattern recognition systemmay be used to determine the location of the occupant's head from theplurality of distance measurements from the illumination sensor systemto the different portions of the occupant and the head-obscuringobjects. The processor, using the pattern recognition system, determinesthe location of the occupant's head. The pattern recognition system maybe a neural network.

The head location sensor system may be arranged to determine thelocation of the approximate longitudinal location of the head from theheadrest. If the vehicle includes at least one airbag, the sensor systemmay be arranged to determine the location of the occupant's headrelative to the airbag(s). The crash sensor system may include anultrasonic transducer or an electromagnetic wave transducer, a systemfor measuring the distance from the vehicle to the object, and/or asystem for recognizing a pattern of the object to thereby identify theobject.

The sensor system may include a switch which is contacted by theoccupant's head and then causes the headrest movement system to stopmovement of the headrest. Instead, the sensor system may include aproximity sensor which is arranged to detect when the headrest isproximate the occupant's head and then cause the headrest movementsystem to stop movement of the headrest. The sensor system may alsoinclude a contact sensor arranged in the headrest which is contacted bythe occupant's head and then causes the headrest movement system to stopmovement of the headrest.

The headrest may include a frame attached to the seat, an airbagcontaining air in a pre-inflated condition, a system for maintaining theairbag in the pre-inflated condition prior to an impact of the headrestagainst the occupant's head, a supporting structure attached to theframe containing the pre-inflated airbag and constraining the motion ofthe pre-inflated airbag to a substantially fore and aft direction, and acover substantially surrounding the pre-inflated airbag. The cover iselastically deformable in response to pressures from the pre-inflatedairbag. When the occupant's head is impacted by the headrest, air withinthe pre-inflated airbag flows substantially within the airbag to changethe shape of the airbag so as to approximately conform to the head andneck of the occupant. A flow restriction may be provided in the airbagto permit the controlled flow of air out of the airbag during the impactof the headrest against the occupant's head to thereby dampen the impactof the occupant's head onto the headrest.

A method for positioning a headrest of a seat in a vehicle inanticipation of a rear impact into the vehicle in accordance with theinvention includes determining the location of the head relative to theheadrest, determining when an object external of the vehicle isapproaching the rear of the vehicle at a velocity above a predeterminedvelocity which is indicative of a pending rear impact between the objectand the vehicle, and positioning the headrest adjacent a head of theoccupant when a determination is made that the object is approaching ata velocity above the predetermined velocity and the determined locationof the headrest is not adjacent the occupant's head. The headrest may bepositioned adjacent the occupant's head prior to the impact.

Other objects and advantages of the present invention will becomeapparent from the following description of the preferred embodimentstaken in conjunction with the accompanying drawings. Also, objects ofother inventions disclosed herein are set forth in the '881 application.

BRIEF DESCRIPTION OF THE DRAWINGS

The following drawings are illustrative of embodiments of the systemdeveloped or adapted using the teachings of this invention and are notmeant to limit the scope of the invention as encompassed by the claims.In particular, the illustrations below are frequently limited to themonitoring of the front passenger seat for the purpose of describing thesystem. Naturally, the invention applies as well to adapting the systemto the other seating positions in the vehicle and particularly to thedriver and rear passenger positions.

FIG. 1 is perspective view with portions cut away of a motor vehiclehaving a movable headrest and an occupant sitting on the seat with theheadrest adjacent the head of the occupant to provide protection in rearimpacts.

FIG. 2 is a perspective view of the rear portion of the vehicle shown inFIG. 1 showing a rear crash anticipatory sensor connected to anelectronic circuit for controlling the position of the headrest in theevent of a crash.

FIG. 3 is a perspective view of a headrest control mechanism mounted ina vehicle seat and ultrasonic head location sensors consisting of onetransmitter and one receiver plus a head contact sensor, with the seatand headrest shown in phantom.

FIG. 4 is a perspective view of a female vehicle occupant having a largehairdo and also showing switches for manually adjusting the position ofthe headrest.

FIG. 5 is a perspective view of a male vehicle occupant wearing a wintercoat and a large hat.

FIG. 6 is view similar to FIG. 3 showing an alternate design of a headsensor using one transmitter and three receivers for use with a patternrecognition system.

FIG. 7 is a schematic view of an artificial neural network patternrecognition system of the type used to recognize an occupant's head.

FIG. 8 is a perspective view of a system for automatically adjusting ahead and neck supporting headrest.

FIG. 8A is a perspective view with portions cut away and removed of theheadrest of FIG. 7.

FIG. 9A is a side view of an occupant seated in the driver seat of anautomobile with the headrest in the normal position.

FIG. 9B is a view as in FIG. 8A with the headrest in the head contactposition as would happen in anticipation of a rear crash.

FIG. 10A is a side view of an occupant seated in the driver seat of anautomobile having an integral seat and headrest and an inflatablepressure controlled bladder with the bladder in the normal position.

FIG. 10B is a view as in FIG. 9A with the bladder expanded in the headcontact position as would happen in anticipation of, e.g., a rear crash.

FIG. 11A is a side view of an occupant seated in the driver seat of anautomobile having an integral seat and a pivotable headrest and bladderwith the headrest in the normal position.

FIG. 11B is a view as in FIG. 10A with the headrest pivoted in the headcontact position as would happen in anticipation of, e.g., a rear crash.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Note whenever a patent or literature is referred to below it is to beassumed that all of that patent or literature is to be incorporated byreference in its entirety to the extent the disclosure of thesereference is necessary.

The invention relates primarily to protection for one or more occupantsof a vehicle during and/or after a rear impact. Rear impact protectionis discussed at length in the parent '957 application, and any and alldiscussions of rear impact safety devices and any and all apparatus andtechniques that can be used in combination with rear impact safetydevices, basically all of the apparatus and techniques described in theparent '957 application, are incorporated herein. For example, arear-of-head detector 423 is illustrated in FIG. 68 of the '957application. This detector 423, which can be one of the types describedabove, is used to determine the distance from the headrest to therearmost position of the occupant's head and to therefore control theposition of the headrest so that it is properly positioned behind theoccupant's head to offer optimum support during a rear impact. Althoughthe headrest of most vehicles is adjustable, it is rare for an occupantto position it properly if at all. Each year there are in excess of400,000 whiplash injuries in vehicle impacts approximately 90,000 ofwhich are from rear impacts (source: National Highway Traffic SafetyAdmin.). A properly positioned headrest could substantially reduce thefrequency of such injuries, which can be accomplished by the headdetector of this invention. The head detector 423 is shown connectedschematically to the headrest control mechanism and circuitry 424. Thismechanism is capable of moving the headrest up and down and, in somecases, rotating it fore and aft.

Referring to FIGS. 1-11B wherein like reference characters refer to thesame or similar elements, FIG. 1 is perspective view with portions cutaway of a motor vehicle, shown generally at 1, having two movableheadrests 356 and 359 and an occupant 30 sitting on the seat with theheadrest 356 adjacent a head 33 of the occupant to provide protection inrear impacts.

In FIG. 2, a perspective view of the rear portion of the vehicle shownin FIG. 1 is shown with a rear impact crash anticipatory sensor,comprising a transmitter 440 and two receivers 441 and 442, connected byappropriate electrical connections, e.g., wire 443, to an electroniccircuit or control module 444 for controlling the position of theheadrest in the event of a crash. In commonly owned U.S. Pat. No.6,343,810 an anticipatory sensor system for side impacts is disclosed.This sensor system uses sophisticated pattern recognition technology todifferentiate different categories of impacting vehicles. A side impactwith a large truck at 20 mph is more severe than an impact with amotorcycle at 40 mph, and, since in that proposed airbag system thedriver would no longer be able to control the vehicle, the airbag mustnot be deployed except in life threatening situations. Therefore, it iscritical in order to predict the severity of a side impact, to know thetype of impacting vehicle.

To improve the assessment of the impending crash, the crash sensor willoptimally determine the position and velocity of an approaching object.The crash sensor can be designed to use differences between thetransmitted and reflected waves to determine the distance between thevehicle and the approaching object and from successive distancemeasurements, the velocity of the approaching object. In this regard,the difference between the transmitted and received waves or pulses maybe reflected in the time of flight of the pulse, a change in the phaseof the pulse and/or a Doppler radar pulse, or by range gating anultrasonic pulse, an optical pulse or a radar pulse. As such, the crashsensor can comprise a radar sensor, a noise radar sensor, a camera, ascanning laser radar and/or a passive infrared sensor.

The situation is quite different in the case of rear impacts and theheadrest system described herein. The movement of the headrest to theproximity of an occupant's head is not likely to affect his or herability to control the automobile. Also, it is unlikely that anythingbut another car or truck will be approaching the rear of the vehicle ata velocity relative to the vehicle of greater than 8 mph, for example.The one exception is a motorcycle and it would not be serious if theheadrest adjusted in that situation. Thus, a simple ranging sensor isall that is necessary. There are, of course, advantages in using a moresophisticated pattern recognition system as will be discussed below.

FIG. 2, therefore, illustrates a simple ranging sensor using atransmitter 440 and two receivers 441 and 442. Transmitter 440 may beany wave-generating device such as an ultrasonic transmitter while thereceivers 441,442 are compatible wave-receiving devices such asultrasonic receivers. The ultrasonic transmitter 440 transmitsultrasonic waves. These transducers are connected to the electroniccontrol module (ECM) 444 by means of wire 443, although other possibleconnecting structure (wired or wireless) may also be used in accordancewith the invention. Other configurations of the transmitter 440,receivers 441,442 and ECM 444 might be equally or more advantageous. Thesensors determine the distance of the approaching object and determineits velocity by differentiating the distance measurements or by use ofthe Doppler effect or other appropriate method. Although an ultrasonicsystem is illustrated herein, radar, electromagnetic, e.g., optical, orother systems could also be used as well as any appropriate number oftransmitters and receivers.

Although a system based on ultrasonics is generally illustrated anddescribed above and represents one of the best mode of practicing thisinvention, it will be appreciated by those skilled in the art that othertechnologies employing electromagnetic energy such as optical, infrared,radar, capacitance etc. could also be used. Also, although the use ofreflected energy is disclosed, any modification of the energy by anobject behind the vehicle is contemplated including absorption, phasechange, transmission and reemission or even the emission or reflectionof natural radiation. Such modification can be used to determine thepresence of an object behind the vehicle and the distance to the object.

Thus, the system for determining the location of the head of theoccupant can comprise an electric field sensor, a capacitance sensor, aradar sensor, an optical sensor, a camera, a three-dimensional camera, apassive infrared sensor, an ultrasound sensor, a stereo sensor, afocusing sensor and a scanning system. One skilled in the art would beable to apply these systems in the invention in view of the disclosureherein and the knowledge of the operation of such systems attributed toone skilled in the art.

Although pattern recognition systems, such as neural nets, might not berequired, such a system would be desirable. With pattern recognition,other opportunities become available such as the determination of thenature of objects behind the vehicle. This could be of aid in locatingand recognizing objects, such as children, when vehicles are backing upand for other purposes. Although some degree of pattern recognition canbe accomplished with the system illustrated in FIG. 2, especially if anoptical system is used instead of the ultrasonic system illustrated,additional transducers significantly improve the accuracy of the patternrecognition systems if either ultrasonics or radar systems are used.

The wire 443 shown in FIG. 2 leads to the electronic control module 444which is also shown in FIG. 3. FIG. 3 is a perspective view of aheadrest actuation mechanism, mounted in a vehicle seat 4, andtransducers 353,354 plus a head contact sensor 334. Transducer 353 maybe an ultrasonic transmitter and transducer 354 may be an ultrasonicreceiver. The transducers 353,354 may be based on any type ofpropagating phenomenon such as electromagnetics (for example capacitivesystems), and are not limited to use with ultrasonics. The seat 4 andheadrest 356 are shown in phantom. Vertical motion of the headrest 356is accomplished when a signal is sent from control module 444 toservomotor 374 through wire 376. Servomotor 364 rotates lead screw 377which mates with a threaded hole in elongate member 378 causing it tomove up or down depending on the direction of rotation of the lead screw377. Headrest support rods 379 and 380 are attached to member 378 andcause the headrest 356 to translate up or down with member 378. In thismanner, the vertical position of the headrest 356 can be controlled asdepicted by arrow A-A.

Wire 381 leads from the control module 444 to servomotor 375 whichrotates lead screw 382. Lead screw 382 mates with a threaded hole inelongate, substantially cylindrical shaft 383 which is attached tosupporting structures within the seat shown in phantom. The rotation oflead screw 382 rotates servo motor support 384 which in turn rotatesheadrest support rods 379 and 380 in slots 385 and 386 in the seat 4. Inthis manner, the headrest 356 is caused to move in the fore and aftdirection as depicted by arrow B-B. There are other designs whichaccomplish the same effect of moving the headrest to where it isproximate to the occupant's head

The operation of the system is as follows. When an occupant is seated ona seat containing the headrest and control system described above, thetransducer 353 emits ultrasonic energy which reflects off of the back ofthe head of the occupant and is received by transducer 354. Anelectronic circuit containing a microprocessor determines the distancefrom the head of the occupant based on the time period between thetransmission and reception of an ultrasonic pulse. The headrest 356moves up and/or down until it finds the vertical position at which it isclosest to the head of the occupant. The headrest remains at thatposition. Based on the time delay between transmission and reception ofan ultrasonic pulse, the system can also determine the longitudinaldistance from the headrest to the occupant's head. Since the head maynot be located precisely in line with the ultrasonic sensors, or theoccupant may be wearing a hat, coat with a high collar, or may have alarge hairdo, there may be some error in the longitudinal measurement.This problem is solved in an accident through the use of a contactswitch 334 on the surface of the headrest. When the headrest contacts ahard object, such as the rear of an occupant's head, the contact switch334 closes and the motion of the headrest stops.

Although a system based on ultrasonics is generally illustrated anddescribed above and represents the best mode of practicing thisinvention, it will be appreciated by those skilled in the art that othertechnologies employing electromagnetic energy such as optical, infrared,radar, capacitance etc. could also be used. Also, although the use ofreflected energy is disclosed, any modification of the energy by theoccupant's head is contemplated including absorption, capacitancechange, phase change, transmission and reemission. Such modification canbe used to determine the presence of the occupant's head adjacent theheadrest and/or the distance between the occupant's head and theheadrest.

When a vehicle approaches the target vehicle, the target vehiclecontaining the headrest and control system of this invention, the timeperiod between transmission and reception of ultrasonic waves, forexample, shortens indicating that an object is approaching the targetvehicle. By monitoring the distance between the target vehicle and theapproaching vehicle, the approach velocity of the approaching vehiclecan the calculated and a decision made by the circuitry in controlmodule 444 that an impact above a threshold velocity is about to occur.The control module 444 then sends signals to servo motors 375 and 374 tomove the headrest to where it contacts the occupant in time to supportthe occupant's head and neck and reduce or eliminate a potentialwhiplash injury as explained in more detailed below.

The seat also contains two switch assemblies 388 and 389 for controllingthe position of the seat 4 and headrest 356. The headrest controlswitches 389 permit the occupant to adjust the position of the headrestin the event that the calculated position is uncomfortably close to orfar from the occupant's head. A woman with a large hairdo might findthat the headrest automatically adjusts so as to contact her hairdo.This might be annoying to the woman who could then position the headrestfurther from her head. For those vehicles which have a seat memorysystem for associating the seat position with a particular occupant, theposition of the headrest relative to the occupant's head can also berecorded. Later, when the occupant enters the vehicle, and the seatautomatically adjusts to the occupant's recorded in memory preference,the headrest will similarly automatically adjust. In U.S. Pat. No.5,822,437, a method of passively recognizing a particular occupant isdisclosed.

Thus, an automatic adjustment results which moves the headrest to eachspecific occupant's desired and memorized headrest position. Theidentification of the specific individual occupant, for which memorylook-up or the like would occur, can be by height sensors, weightsensors (for example placed in a seat), or by pattern recognitionsystems, or a combination of these and other systems or techniques, asdisclosed herein, in the parent '957 application, and in theabove-referenced patent applications and granted patents.

One advantage of this system is that it moves the headrest toward theoccupant's head until it senses a resistance characteristic of theoccupant's head. Thus, the system will not be fooled by a high coatcollar 445 or hat 446, as illustrated in FIG. 5, or other article ofclothing or by a large hairdo 447 as illustrated in FIG. 4. The headrestcontinues to be moved until it contacts something relatively rigid asdetermined by the contact switch 334.

A key advantage of this system is that there is no permanent damage tothe system when it deploys during an accident. After the event it willreset without an expensive repair. In fact, it can be designed to resetautomatically.

An ultrasonic sensor in the headrest has previously been proposed in aU.S. patent to locate the occupant for the out-of-position occupantproblem. In that system, no mention is made as to how to find the head.In the headrest location system described herein, the headrest can bemoved up and down in response to the instant control systems to find thelocation of the back of the occupant's head. Once it has been found thesame sensor is used to monitor the location of the person's head. Othermethods of finding the location of the head of an occupant are possibleincluding in particular an electromagnetic based system such as acamera, capacitance sensor or electric field sensor.

An improvement to the system described above results when patternrecognition technology is added. FIG. 6 is view similar to FIG. 3showing an alternate design of a head sensor using three transducers353, 354 and 355 which can be used with a pattern recognition system.Transducer 353 can perform both as a transmitter and receiver whiletransducers 354,355 can perform only as receivers. Transducers 354,355can be placed on either side of and above transducer 353. Using thissystem and an artificial neural network, or other pattern recognitionsystem, as part of the electronic control module 444, or elsewhere, anaccurate determination of the location of an occupant's head can, inmost cases, be accomplished even when the occupant has a large hairdo orhat. In this case, the system can be trained for a wide variety ofdifferent cases prior to installation into the vehicle. This training isaccomplished by placing a large variety of different occupants onto thedriver's seat in a variety of different positions and recordingdigitized data from transducers 353, 354 and 355 along with datarepresenting the actual location of the occupant's head. The differentoccupants include examples of large and small people, men and women,with many hair, hat, and clothing styles. Since each of these occupantsis placed at a variety of different positions on the seat, the totaldata set, called the “training set”, can consist of at least onethousand, and typically more than 100,000, cases. This training set isthen used to train the neural network, or other similar trainablepattern recognition technology, so that the resulting network can locatethe occupant's head in the presence of the types of obstructionsdiscussed above whatever an occupant occupies the driver's seat.

FIG. 7 is a schematic view of an artificial neural network of the typeused to recognize an occupant's head and is similar to that presented inFIG. 19B of the '957 application. The theory of neural networksincluding many examples can be found in several books on the subjectincluding: Techniques And Application Of Neural Networks, edited byTaylor, M. and Lisboa, P., Ellis Horwood, West Sussex, England, 1993;Naturally Intelligent Systems, by Caudill, M. and Butler, C., MIT Press,Cambridge Mass., 1990; and, Digital Neural Networks, by Kung, S. Y., PTRPrentice Hall, Englewood Cliffs, N.J., 1993. the neural network ispresented here as an example of a pattern recognition technology. Otherpattern recognition algorithms, such as neural-fuzzy systems, are beingdeveloped which, in some cases, have superior performance to pure neuralnetworks.

The process of locating the head of an occupant can be programmed tobegin when an event occurs such as the closing of a vehicle door or theshifting of the transmission out of the PARK position. The ultrasonictransmitting/receiving transducer 353, for example, transmits a train ofultrasonic waves toward the head of the occupant. Waves reflected fromthe occupant's head are received by transducers 353, 354 and 355. Anelectronic circuit containing an analog to digital converter convertsthe received analog signal to a digital signal which is fed into theinput nodes numbered 1, 2, 3, . . . , n, shown on FIG. 7. The neuralnetwork algorithm compares the pattern of values on nodes 1 through Nwith patterns for which it has been trained, as discussed above. Each ofthe input nodes is connected to each of the second layer nodes, calledthe hidden layer, either electrically as in the case of a neuralcomputer or through mathematical functions containing multiplyingcoefficients called weights, described in more detail below. The weightsare determined during the training phase while creating the neuralnetwork as described in detail in the above text references. At eachhidden layer node a summation occurs of the values from each of theinput layer nodes, which have been operated on by functions containingthe weights, to create a node value. Although an example usingultrasound has been described, the substitution of other sensors such asoptical, radar or capacitors will now be obvious to those skilled in theart.

The hidden layer nodes are in like manner connected to the output layernodes, which in this example is only a single node representing thelongitudinal distance to the back of the occupant's head. During thetraining phase, the distance to the occupant's head for a large varietyof patterns is taught to the system. These patterns include cases wherethe occupant is wearing a hat, has a high collar, or a large hairdo, asdiscussed above, where a measurement of the distance to the back of theoccupant's head cannot be directly measured. When the neural networkrecognizes a pattern similar to one for which it has been trained, itthen knows the distance to the occupant's head. The details of thisprocess are described in the above listed referenced texts and will notbe presented in detail here. The neural network pattern recognitionsystem described herein is one of a variety of pattern recognitiontechnologies which are based on training. The neural network ispresented herein as one example of the class of technologies referred toas pattern recognition technologies. Ultrasonics is one of manytechnologies including optical, infrared, capacitive, radar, electricfield or other electromagnetic based technologies. Although thereflection of waves was illustrated, any modification of the waves bythe head of the occupant is anticipated including absorption,capacitance change, phase change, transmission and reemission.Additionally, the radiation emitted from the occupant's head can be useddirectly without the use of transmitted radiation. Combinations of theabove technologies can be used.

A time step, such as one tenth of a millisecond, is chosen as the periodat which the analog to digital converter (ADC) averages the output fromthe ultrasonic receivers and feeds data to the input nodes. For onepreferred embodiment of this invention, a total of one hundred inputnodes is typically used representing ten milliseconds of received data.The input to each input node is a preprocessed combination of the datafrom the three receivers. In another implementation, separate inputnodes would be used for each transducer. Alternately, the input data tothe nodes can be the result of a preprocessing algorithm which combinesthe data taking into account the phase relationships of the three returnsignals to obtain a map or image of the surface of the head using theprinciples of phased array radar. Although a system using onetransmitter and three receivers is discussed herein, where onetransducer functions as both a transmitter and receiver, even greaterresolution can be obtained if all three receivers also act astransmitters.

In the example above, one hundred input nodes, twelve hidden layer nodesand one output layer node are typically used. In this example receiveddata from only three receivers were considered. If data from additionalreceivers is also available the number of input layer nodes couldincrease depending on the preprocessing algorithm used. If the sameneural network is to be used for sensing rear impacts, one or moreadditional output nodes might be used, one for each decision. The theoryfor determining the complexity of a neural network for a particularapplication has been the subject of many technical papers as well as inthe texts referenced above and will not be presented in detail here.Determining the requisite complexity for the example presented here canbe accomplished by those skilled in the art of neural network design andis discussed briefly below.

The pattern recognition system described above defines a method ofdetermining the probable location of the rear of the head of an occupantand, will therefore determine, if used in conjunction with theanticipatory rear impact sensor, where to position a deployable occupantprotection device in a rear collision, and comprises:

(a) obtaining an ultrasonic, analog signal from transducers mounted inthe headrest;

(b) converting the analog signal into a digital time series;

(c) entering the digital time series data into a pattern recognitionsystem such as a neural network;

(d) performing a mathematical operation on the time series data todetermine if the pattern as represented by the time series data isnearly the same as one for which the system has been trained; and

(e) calculating the probable location of the occupant's head if thepattern is recognizable.

The particular neural network described and illustrated above contains asingle series of hidden layer nodes. In some network designs, more thanone hidden layer is used although only rarely will more than two suchlayers appear. There are of course many other variations of the neuralnetwork architecture illustrated above, as well as other patternrecognition systems, which appear in the literature. For the purposesherein, therefore, “neural network” can be defined as a system whereinthe data to be processed is separated into discrete values which arethen operated on and combined in at least a two stage process and wherethe operation performed on the data at each stage is in generaldifferent for each of the discrete values and where the operationperformed is at least determined through a training process. Theoperation performed is typically a multiplication by a particularcoefficient or weight and by different operation, therefore is meant inthis example, that a different weight is used for each discrete value.

The implementation of neural networks can take at least two forms, analgorithm programmed on a digital microprocessor or in a neuralcomputer. Neural computer chips are now available.

In the particular implementation described above, the neural network istypically trained using data from 1000 or more than 100,000 differentcombinations of people, clothes, wigs etc. There are, of course, othersituations which have not been tested. As these are discovered,additional training will improve the performance of the patternrecognition head locator.

Once a pattern recognition system is implemented in a vehicle, the samesystem can be used for many other pattern recognition functions asdescribed herein and in the above referenced patents and patentapplications. For example, in the current assignee's U.S. Pat. No.5,829,782 referenced above, the use of neural networks as a preferredpattern recognition technology is disclosed for use in identifying arear facing child seat located on the front passenger seat of anautomobile. This same patent application also discloses many otherapplications of pattern recognition technologies for use in conjunctionwith monitoring the interior of an automobile passenger compartment.

As described in the above referenced patents to Dellanno and Dellanno etal., whiplash injuries typically occur when there is either no headsupport or when only the head of the occupant is supported during a rearimpact. To minimize these injuries, both the head and neck should besupported. In Dellanno, the head and neck are supported through apivoting headrest which first contacts the head of the occupant and thenrotates to simultaneously support both the head and the neck. The forceexerted by the head and neck onto the pivoting headrest is distributedbased on the relative masses of the head and neck. Dellanno assumes thatthe ratio of these masses is substantially the same for all occupantsand that the distances between centers of mass of the head and neck isapproximately also proportional for all occupants. To the extent thatthis is not true, a torque will be applied to the headrest and cause acorresponding torque to be applied to the head and neck of the occupant.Ideally, the head and neck would be supported with just the requiredforce to counteract the inertial force of each item. Obviously this canonly approximately be accomplished with the Dellanno pivoting headrestespecially when one considers that no attempt has been made to locatethe headrest relative to the occupant and the proper headrest positionwill vary from occupant to occupant. Dellanno also assumes that the headand neck will impact and in fact bounce off of the headrest. This infact can increase the whiplash injuries since the change in velocity ofthe occupant's head will be greater that if the headrest absorbed thekinetic energy and the head did not rebound. A far more significantimprovement to eliminating whiplash injuries can be accomplished byeliminating this head impact and the resulting rebound as isaccomplished in the present invention.

Automobile engineers attempt to design vehicle structures so that in animpact the vehicle is accelerated at an approximately constantacceleration. It can be shown that this results in the most efficientuse of the vehicle structure in absorbing the crash energy. It alsominimizes the damage to the vehicle in a crash and thus the cost ofrepair. Let us assume, therefore, that in a particular rear impact thatthe vehicle accelerates at a constant 15 g acceleration. Let us alsoassume that the vehicle seat back is rigidly attached to the vehiclestructure at least during the early part of the crash, so that up untilshortly after the occupant's head has impacted the headrest the seatback also is accelerating at a constant 15 g's. Finally let us assumethat the occupant's head is initially displaced 4 inches from theheadrest and that during impact the head compresses the headrest 1 inch.When the occupant's head impacts the headrest it must now make up forthe difference in velocity between the headrest and the head during theperiod that it is compressing the headrest 1 inch. It can bedemonstrated that this requires an acceleration of approximately 75 g'sor five times the acceleration which the head would experience if itwere in contact with the headrest at the time that the rear impactoccurs.

The Dellanno headrest, as shown for example in FIG. 3 of U.S. Pat. No.5,290,091, is a worthwhile addition to solving the whiplash problemafter the headrest has been positioned against the head and neck of theoccupant. The added value of the Dellanno design over simpler designs,especially considering the inertial effects of having to rapidly rotatethe headrest while the crash is taking place, is probably not justified.FIG. 8 illustrates a headrest design which accomplishes the objectivesof the Dellanno headrest in a far simpler structure and at lesspotential injury to the occupant.

In FIG. 8, a seat with a movable headrest similar to the one illustratedin FIG. 3 is shown with a headrest designated 450 designed to providesupport to both the head and neck which eliminates the shortcomings ofthe Dellanno headrest. The ultrasonic transducer 353, which includesboth a transmitter and receiver, has been moved to an upper portion ofthe seat back, not the headrest, to facilitate the operation of thesupport system as described below. The construction of the headrest isillustrated in a cutaway view shown in FIG. 8A which is an enlarged viewof the headrest of FIG. 8.

In FIG. 8A, the headrest is constructed of a support or frame 452 whichis attached to rods 379 and 380 and extends along the sides and acrossthe back of the headrest. Support 452 may be made of a somewhat rigidmaterial. This support 452 helps control the motion of a pre-inflatedbag 453 as it deforms under the force from the head of the occupant towhere it contacts and provides support to the occupant's neck.Relatively low density open cell foam 454 surrounds the support 452giving shape to the remainder of the headrest. As shown in FIG. 8A, theopen call foam 454 can also have channels or openings 455 extending in adirection generally from a top of the headrest 450 to a bottom of theheadrest 450, although such channels are not required. The direction ofthe channels or openings 455 facilitates the desired movement of thefluid in the bag 453 and constrains the fluid flow upon impact of theoccupant's head against the headrest 450, i.e., a generally verticalmovement in the case of the illustrated headrest 450. The open call foam454 is covered by a thin membrane, possibly made from plastic, or thebag 453 (also referred to as an airbag herein which is appropriate whenthe fluid in the bag 453 is air—although the fluid within bag 453 may beother than air), and by a decorative cover 456 made of any suitable,acceptable material. The bag 453 is sealed surrounding the support 452and plastic or rubber foam 454 such that any flow of fluid such as airinto or out of the bag 453 is through a hole in the bag 453 adjacent toa vent hole 451 in the supporting structure, i.e., the cover 456.Elastic stretch seams 457 can be placed in the sides, bottom and/oracross the front of the headrest cover to permit the headrest surface todeform to the contour of, and to properly support, the occupant's headand neck. A contact switch 334 is placed just inside cover 456 andfunctions as described above.

Instead of channels, the properties of the foam can be selected toprovide the desired flow of gas, e.g., the design, shape, positioningand construction of the foam can be controlled and determined duringmanufacture to obtain the desired flow properties.

FIGS. 9A and 9B illustrate the operation of the headrest 450. Inanticipation of a rear impact (or any other type of impact), asdetermined by the proximity sensors described above or any otheranticipatory crash sensor system, headrest 450 is moved from itsposition as shown in FIG. 9A to its position as shown in FIG. 9B. Thismovement is enabled by control of the displacement mechanism, such asthose described above with reference to FIG. 3, as effected through thecontrol module 444. The forward movement of the headrest 450 shouldcontinue until the headrest 450 contacts or impacts with the occupant'shead as determined by a contact switch 334. When headrest 450 contactsor impacts the head 33 of the occupant 30, it exerts sufficient pressureagainst head 33 to cause air (the fluid in the bag 453 for the purposesof this explanation) to flow from the upper portion 458 to the lowerportion 459 of headrest 450, which causes this lower portion to expandas the upper portion contracts. This initial flow of air takes place asthe foam 454 compresses under the force of contact between the head andupper portion 458 of headrest 450. The initial shape of headrest 450 iscreated by the shape of the foam 454; however once the occupants head 33begins to exert pressure on the upper portion 458 the air is compressedand begins to flow to the lower portion 459 causing it to expand untilit contacts the neck 460 of the occupant 30. (If the occupant's headwere to exert pressure on the lower portion 459 or once the pressure onthe upper portion 458 were removed, air would flow from the lowerportion 459 to the upper portion 458.) In this manner, by the flow ofair, the pressure is equalized on the head and neck of the occupant 30thereby preventing the whiplash type motions described in the Dellannopatents, as well as numerous technical papers on the subject. Theheadrest of this invention acts very much like a pre-inflated airbagproviding force where force is needed to counteract the accelerations ofthe occupant. It accomplishes this force balancing without the need torotate a heavy object such as the headrest in the Dellanno patent whichby itself could introduce injuries to the occupant.

In addition to use as a headrest, the structure described above can beused in other applications for cushioning an occupant of a vehicle,i.e., for cushioning another part of the occupant's body in an impact.The cushioning arrangement would thus comprise a frame or supportcoupled to the vehicle and a fluid-containing bag attached to the frameor other support. A deformable cover would also be preferred. The bag,including the cell foam and vent hole as described above, would allowmovement of the fluid within the bag to thereby alter the shape of thebag, upon contact with the part of the occupant's body, and enable thebag to conform to the part of the occupant's body. This wouldeffectively cushion the occupant's body during an impact. Further, thecushioning arrangement could be coupled to the anticipatory crash sensorthrough a control unit (i.e., control module 444) and displacementmechanism in a similar manner as headrest 450, to thereby enablemovement of the cushioning arrangement against the part of theoccupant's body just prior to or coincident with the crash.

A headrest using a pre-inflated airbag type structure composed of manysmall airbags is disclosed in FIG. 9 of U.S. Pat. No. 5,098,124 to Breedet al. The headrest disclosed here differs primarily through the use ofa single pre-inflated fluid-containing bag, fluid-filled bag or airbagwhich when impacted by the head of the occupant, deforms by displacingthe surface of the headrest outwardly to capture and support the neck ofthe occupant. The use of an airbag to prevent whiplash injuries iscommon for accidents involving frontal impacts and driver and passengerside airbags. Whiplash injuries have not become an issue in frontalimpacts involving airbags, therefore, the ability of airbags to preventwhiplash injuries in frontal impacts is proven. The use of airbags toprevent whiplash injuries in rear impacts is therefore appropriate and,if a pre-inflated airbag as described herein is used, results in asimple low-cost and effective headrest design. Other airbag designs arepossible although the pre-inflated design as described herein ispreferred.

This pre-inflated airbag headrest has another feature which furtherimproves its performance. The vent hole 451 is provided to permit someof the air in the headrest to escape in a controlled manner therebydampening the motion of the head and neck much in the same way that adriver side airbag has vent holes to dissipate the energy of theimpacting driver during a crash. An appropriate regulation device mayalso be associated with the vent hole 451 of the headrest 450 toregulate the escaping air. Without the vent hole, there is risk that theoccupant's head and neck will rebound off of the headrest, as is also aproblem in the Dellanno patents. This can happen especially when, due topre-crash braking or an initial frontal impact such as occurs in amultiple car accident, the occupant is sufficiently out of position thatthe headrest cannot reach his or her head before the rear impact.Without this feature the acceleration on the head will necessarily begreater and therefore the opportunity for injury to the neck isincreased. The size of this hole is determined experimentally or bymathematical analysis and computer simulation. If it is too large, toomuch air will escape and the headrest will bottom out on the support. Ifit is too small, the head will rebound off of the headrest therebyincreasing the chance of whiplash injury. A region of controlledporosity could be substituted for hole 451.

Finally, a side benefit of this invention is that it can be used todetermine the presence of an occupant on the front passenger seat. Thisinformation can then be used to suppress deployment of an airbag if theseat is unoccupied.

FIG. 10A is a side view of an occupant seated in the driver seat of anautomobile having an integral seat and headrest and an inflatablepressure controlled bladder with the bladder in the normal, uninflatedcondition. FIG. 10B is a view as in FIG. 10A with the bladder expandedin the head contact position as would happen in anticipation of, e.g., arear crash.

The seat containing the bladder system of this embodiment of theinvention is shown generally at 465. The seat 465 contains an integralbladder 466 arranged within the cover of the seat 465, afluid-containing chamber 467 connected to the bladder 466 and a smalligniter assembly 468, which contains a small amount, such as about 5grams, of a propellant such as boron potassium nitrate. Upon receiving asignal that a crash is imminent, igniter assembly 468 is ignited andsupplies a small quantity of hot propellant gas into chamber 467. Thegas (the fluid in a preferred embodiment) in chamber 467 then expandsdue to the introduction of the high temperature gas and causes thebladder 466 to expand to the condition shown in FIG. 10B. Bladder 466expands in such a manner (through its design, construction and/orpositioning and/or through the design and construction of the seat 465)as to conform to the shape of the occupant's head 33 and neck 460. Assoon as the expanding headrest portion 469 of the seat 465 contacts thehead 33 and neck 460 of the occupant (as may be determined by a contactsensor in the seat 465), pressure begins to increase in the bladder 466causing a control valve 470 to open and release gas into the passengercompartment to thereby prevent the occupant from being displaced towardthe front of the vehicle.

Control valve 470 is situated in a flow line between the bladder 466 andan opening in the rear of the seat 465 in the illustrated embodiment,but may be directly connected to the bladder 466. The flow line may bedirected to another location, e.g., the exterior of the vehicle, throughappropriate conduits. Control valve 470 can be controlled by anappropriate control device, such as the central diagnostic module, andthe amount of gas released coordinated with or based on the severity ofthe crash or any other parameter of the crash or deployment of theairbag.

In the examples of FIGS. 10A and 10B, a small pyrotechnic element isutilized as the igniter assembly 468; however, the system itself isautomatically resetable. Thus, after the impact, the system returns toits pre-inflated position and the only part that needs to be replaced isthe igniter assembly 468. The cost of restoring the system after anaccident is therefore small. The igniter assembly 468 may be positionedso that it can be readily accessed from the rear of the seat, e.g., byremoving a panel in the rear of the seat. The igniter assembly 468 maybe coupled directly or indirectly to a crash sensor, possibly through acentral diagnostic module of the vehicle. The crash sensor is preferablyan anticipatory crash sensor arranged so as to detect rear impactsbecause whiplash injuries are mostly caused during rear impacts.

In operation, the crash sensor, such as the anticipatory crash sensor ofFIG. 2, detects the impending crash into the rear of the vehicle andgenerates a signal or causes a signal to be generated indicative of thefact that the igniter assembly 468 should be activated to inflate thebladder 466. The igniter assembly 468 is then activated generatingheated gas which is directed into chamber 467. The gas in chamber 467expands and passes through one or more conduits into the bladder 466causing the bladder 466 to expand to the condition shown in FIG. 10B.The expanding bladder 466 will fill in the space between the occupantand the headrest and seat as shown in FIG. 10B. The bladder 466 may bedesigned to have more expansion capability in the head and neck areas asthose surfaces will initially be further from the body of the driver.The inflated bladder 466 will thus reduce the risk of whiplash injuriesto the driver.

The control valve 470 is designed or controlled to ensure that thebladder 466 expands sufficiently to provide whiplash protection withoutexerting a forward force of the driver. For example, the pressure in thebladder 466 may be measured during inflation and once it reaches anoptimum level, the control (or pressure release) valve 470 may beactivated. In the alternative, during the design phase, the time ittakes for the bladder 466 to inflate to the optimum level may becomputed and then the control valve 470 designed to activate after thispredetermined time.

Instead of a control valve, it is also possible to use a variableoutflow port or vent as described in the current assignee's U.S. Pat.No. 5,748,473, incorporated by reference herein.

After inflation and the crash, the igniter assembly 468 can be removedand replaced with compatible igniter assembly so that the vehicle isready for subsequent use.

As shown in FIGS. 10A and 10B, the bladder 466 is integral with the seat465 and the headrest of the seat is formed with the backrest as acombined seat back portion. If the headrest is formed separate from thebackrest, then the bladder 466 can be formed integral with the headrestand if necessary, integral with the backrest to achieve the whiplashprotection sought by the invention.

FIG. 11A is a side view of an occupant seated in the driver seat of anautomobile having an integral seat and a pivotable or rotatable headrestand bladder with the headrest in the normal position. FIG. 11B is a viewas in FIG. 11A with the headrest pivoted in the head contact position aswould happen in anticipation of, e.g., a rear crash. In contrast to theembodiment of FIGS. 10A and 10B, this embodiment is purely passive inthat no pyrotechnics are used.

In this embodiment, upon receiving a signal that a crash is imminent,electronic circuitry, not shown, activates solenoid 471 causing headrestportion 474 to rotate about pivot 473 (an axis, pin, etc) toward theoccupant. The system is shown generally at 475 and comprises a seat backportion 472 and headrest portion 474. In FIG. 11B, the headrest portion474 has rotated until it contacts the occupant and then a bladder orairbag 476 within headrest portion 464 changes shape or deforms toconform to the head 33 and neck 460 of the occupant thereby supportingboth the head and neck and preventing a whiplash injury. The control ofthe rotation of the headrest portion 474 can be accomplished either by acontact switch or force measurement using a switch or force sensor inthe headrest or a force or torque sensor at the solenoid 471 or,alternately, by measuring the pressure within the airbag 476. Solenoid471 can be replaced by another linear actuator such as an air cylinderwith an appropriate source of air pressure.

The electronic circuitry, not shown, may be controlled by the centraldiagnostic module or upon receiving a signal from the crash sensor.Airbag 476 is shown arranged within the headrest portion 464, i.e., itis within the periphery of the surface layer of the headrest portion 474and seat 475.

In operation, the crash sensor detects the impending crash, e.g., intothe rear of the vehicle, and generates a signal or causes a signal to begenerated resulting in pivotal movement of the headrest portion 474. Theheadrest portion 474 is moved (pivoted) preferably until a point atwhich the front of the headrest portion 474 touches the back of thedriver's head. This can all occur prior to the actual crash. Thereafter,upon the crash, the driver will be forced backwards against the pivotedheadrest portion 474. Gas will flow from the upper part of the headrestportion 474 and the seat back and thereby distribute the load betweenthe head, neck and body.

As shown in FIGS. 11A and 11B, the headrest portion of the seat isformed with the backrest as a combined seat back portion. If theheadrest is formed separate from the backrest, then the airbag 476 canbe formed integral with the headrest and if necessary, integral with thebackrest to achieve the whiplash protection sought by the invention. Inthis case, the pivot 473 might be formed in the backrest or between thebackrest and headrest.

Although shown for use with a driver, the same systems could be used forpassengers in the vehicle as well, i.e., it could be used for thefront-seat passenger(s) and any rear-seated passengers. Also, althoughwhiplash injuries are most problematic in rear impacts, the same systemcould be used for side impacts as well as front impacts and rolloverswith varying degrees of usefulness.

Thus, disclosed herein is a seat for a vehicle for protecting anoccupant of the seat in a crash which comprises a headrest portion, anexpandable bladder arranged at least partially in the headrest portion,the bladder being arranged to conform to the shape of a neck and head ofthe occupant upon expansion, and an igniter for causing expansion of thebladder upon receiving a signal that protection for the occupant isdesired. The bladder may also be arranged in least partially in thebackrest portion of the seat. A fluid-containing chamber is coupled tothe igniter and in flow communication with the bladder whereby theigniter causes fluid in the chamber to expand and flow into the bladderto expand the bladder. A control valve is associated with the bladderfor enabling the release of fluid from the bladder. The bladder ispreferably arranged in an interior of the headrest portion, i.e., suchthat its expansion is wholly within the outer surface layer of theheadrest portion of the seat. A vehicle including this system can alsoinclude a crash sensor system for determining that a crash requiringprotection for the occupant is desired. The crash sensor systemgenerates a signal and directing the signal to the igniter. The crashsensor system may be arranged to detect a rear impact.

Another seat for a vehicle for protecting an occupant of the seat in acrash disclosed above comprises a backrest including a backrest portionand a headrest portion and an airbag arranged at least partially in theheadrest portion. The headrest portion is pivotable with respect to thebackrest portion toward the occupant. To this end, a pivot structure isprovided for enabling pivotal movement of the headrest portion relativeto the backrest portion. The pivot structure may be a solenoid arrangedto move an arm about a pivot axis, which arm is coupled to the headrestportion. The airbag is arranged in an interior of the headrest portionof the backrest. A vehicle including this system can also include acrash sensor system for determining that a crash requiring protectionfor the occupant is desired. The headrest portion is pivoted intocontact with the occupant upon a determination by the crash sensorsystem that a crash requiring protection for the occupant is desired.The crash sensor system may be arranged to detect a rear impact.

Also disclosed herein is a headrest for a seat which comprises a frameattachable to the seat and a fluid-containing bag attached to the frame.The bag is structured and arranged to allow movement of the fluid withinthe bag to thereby alter the shape of the bag and enable the bag toconform to the head and neck of an occupant. A deformable cover maysubstantially surround the bag such that the bag is within the seat,i.e., an outer surface of the bag is not exposed to the atmosphere. Thecover is elastically deformable in response to changes in pressure inthe bag. The frame may be made of a rigid material. The bag can containcell foam having openings (open cell foam), which in a static state,determines the shape of the bag. The fluid in the bag may be air, i.e.,an airbag. To provide the elastic deformation of the cover, the covermay include stretch seams at one or more locations. Preferably, thestretch seams should be placed on the side(s) of the headrest which willcontour to the shape of the occupant's head and neck upon impact. Thebag may include a constraining mechanism for constraining flow of fluidfrom an upper portion of the headrest to a lower portion of theheadrest. The constraining mechanism may comprise open cell foampossibly with channels extending in a direction from a top of theheadrest to a bottom of the headrest. In the alternative, the propertiesof the foam may be controlled to get the desired flow rate and possiblyflow direction.

The constraining mechanism is structured and arranged such that when theupper portion contracts, the lower portion expands. Also, theconstraining mechanism may be designed so that when the upper portionexpands, the lower portion contracts. The cover and bag are structuredand arranged such that when an occupant impacts the headrest, fluidwithin the bag flows substantially within the bag to change the shape ofthe bag so as to approximately conform to the head and neck of theoccupant thereby providing a force on the head and neck of the occupantto substantially accelerate both the head and neck at substantially thesame acceleration in order to minimize whiplash injuries. The bagpreferably includes a flow restriction which permits a controlled flowof fluid out of the bag upon impact of an object with the headrest tothereby dampen the impact of the object with the headrest.

An inventive seat comprises a seat frame, a bottom cushion, a backcushion cooperating to support an occupant and a headrest attached tothe seat frame. The headrest is as in any of the embodiments describedimmediately above.

An inventive cushioning arrangement for protecting an occupant in acrash comprises a frame coupled to the vehicle and a fluid-containingbag attached to the frame. The bag is structured and arranged to allowmovement of the fluid within the bag to thereby alter the shape of thebag and enable the bag to conform to a portion of the occupant engagingthe cushioning arrangement. The cushioning arrangement should bearranged relative to the occupant such that the bag impacts the occupantduring the crash. As used here (and often elsewhere in thisapplication), “impact” does not necessarily imply direct contact betweenthe occupant and the bag but rather may be considered the exertion ofpressure against the bag caused by contact of the occupant with theouter surface of the cushioning arrangement which is transmitted to thebag. The cushioning arrangement can also include a deformable coversubstantially surrounding the bag. The cover is elastically deformablein response to changes in pressure in the bag. The frame may be coupledto a seat of the vehicle and extends upward from a top of the seat suchthat the cushioning arrangement constitutes a headrest. In thealternative, the cushioning arrangement can be used anywhere in avehicle in a position in which the occupant will potentially impact itduring the crash. The bag and headrest may be as in any of theembodiments described above.

An inventive protection system for protecting an occupant in a crashcomprises an anticipatory crash sensor for determining that a crashinvolving the vehicle is about to occur, and a movable cushioningarrangement coupled to the anticipatory crash sensor. The cushioningarrangement is movable toward a likely position of the occupant,preferably in actual contact with the occupant, upon a determination bythe anticipatory crash sensor that a crash involving the vehicle isabout to occur. The cushioning arrangement comprises a frame coupled tothe vehicle, and a fluid-containing bag attached to the frame. The bagis structured and arranged to allow movement of the fluid within the bagto thereby alter the shape of the bag and enable the bag to conform tothe occupant. The cushioning arrangement and its parts may be asdescribed in any of the embodiments above. The anticipatory crash sensormay be arranged to determine that the crash involving the vehicle is arear impact. In this case, it could comprise a transmitter/receiverarrangement mounted at the rear of the vehicle. To provide for movementof the cushioning arrangement, a displacement mechanism is provided,e.g., a system of servo-motors, screws and support rods, and a controlunit is coupled to the anticipatory crash sensor and the displacementmechanism. The control unit controls the displacement mechanism to movethe cushioning arrangement based on the determination by theanticipatory crash sensor that a crash involving the vehicle is about tooccur.

One disclosed method for protecting an occupant in an impact comprisesdetermining that a crash involving the vehicle is about to occur, andmoving a cushioning arrangement into contact with the occupant upon adetermination that a crash involving the vehicle is about to occur. Thecushioning arrangement comprises a frame coupled to the vehicle and afluid-containing bag attached directly or indirectly to the frame. Thebag is structured and arranged to allow movement of the fluid within thebag to thereby alter the shape of the bag and enable the bag to conformto the occupant. The cushioning arrangement may be as in any of theembodiments described above. The step of moving the cushioningarrangement into contact with the occupant may comprise moving thecushioning arrangement toward the occupant, detecting when thecushioning arrangement comes into contact with the occupant and thenceasing movement of the cushioning arrangement. The step of detectingwhen the cushioning arrangement comes into contact with the occupant maycomprise arranging a contact switch in connection with the cushioningarrangement.

Also disclosed herein is a headrest and headrest positioning systemwhich reduce whiplash injuries from rear impacts by properly positioningthe headrest behind the occupant's head either continuously, or justprior to and in anticipation of, the vehicle impact and then properlysupports both the head and neck. Sensors determine the location of theoccupant's head and motors move the headrest both up and down andforward and back as needed. In one implementation, the headrest iscontinuously adjusted to maintain a proper orientation of the headrestto the rear of the occupant's head. In another implementation, ananticipatory crash sensor, such as described in commonly owned U.S. Pat.No. 6,343,810, is used to predict that a rear impact is about to occur,in which event, the headrest is moved proximate to the occupant.

Also disclosed herein is an apparatus for determining the location ofthe head of the occupant in the presence of objects which obscure thehead. Such an apparatus comprises a transmitter for illuminating aselective portion of the occupant and the head-obscuring objects in thevicinity of the head, a sensor system for receiving illuminationreflected from or modified by the occupant and the head-obscuringobjects and generating a signal representative of the distance from thesensor system to the illuminated portion of the occupant and thehead-obscuring objects, a selective portion changing system for changingthe illuminated portion of the occupant and the head-obscuring objectswhich is illuminated by the transmitter and a processor. The processoris designed to sequentially operate the selective portion changingsystem so as to illuminate different portions of the occupant and thehead-obscuring objects, and a pattern recognition system for determiningthe location of the head from the signals representative of the distancefrom the sensor system to the different selective portions of theoccupant and the head-obscuring objects. The pattern recognition systemmay comprise a neural network. In some embodiments of the invention, thehead-obscuring objects comprise items from the class containing clothingand hair. The pattern recognition system may be arranged to determinethe location of the approximate longitudinal location of the head fromthe headrest. If one or more airbags is mounted within the vehicle, thehead location system may be designed to determine the location of thehead relative to the airbag. The transmitter may comprise an ultrasonictransmitter arranged in the headrest and the sensor system may also bearranged in the headrest, possibly vertically spaced from thetransmitter. In the alternative, the transmitter and sensor system maycomprise a single transducer. The selective portion changing system maycomprise a control module coupled to the transmitter and the sensorsystem and servomotors for adjusting the position of the headrest.

Illumination as used herein is any form of radiation which is introducedinto a volume of which contains the head of an occupant and includes,but it is not limited to, electromagnetic radiation from below one kHzto above ultraviolet optical radiation (10¹⁶ Hz) and ultrasonicradiation. Thus, any system, such as a capacitive system, which uses avarying electromagnetic field, or equivalently electromagnetic waves, ismeant to be included by the term illumination as used herein. Byreflected radiation, it is meant the radiation that is sensed by thedevice that comes from the volume occupied by the head, or other part,of an occupant and indicates the presence of that part of the occupant.Examples of such systems are ultrasonic transmitters and receiversplaced in the headrest of the vehicle seat, capacitive sensors placed inthe headrest or other appropriate location (or a combination oflocations such as one plate of the capacitor being placed in the vehicleseat and the other in the headliner), radar, far or near frequencyinfrared, visible light, ultraviolet, etc.

All of the above-described methods and apparatus may be used inconjunction with one another and in combination with the methods andapparatus for optimizing the driving conditions for the occupants of thevehicle described herein.

Thus there is disclosed and illustrated herein a passive rear impactprotection system which requires no action by the occupant and yetprotects the occupant from whiplash injuries caused by rear impacts.

Although several preferred embodiments are illustrated and describedabove, there are possible combinations using other geometries, sensors,materials and different dimensions for the components that perform thesame functions. Therefore, this invention is not limited to the aboveembodiments and should be determined by the following claims. Inparticular, although the particular rear impact occupant protectionsystem described in detail above requires all of the improvementsdescribed herein to meet the goals and objectives of this invention,some of these improvements may not be used in some applications. Thereare also numerous additional applications in addition to those describedabove. Many changes, modifications, variations and other uses andapplications of the subject invention will, however, become apparent tothose skilled in the art after considering this specification and theaccompanying drawings which disclose the preferred embodiments thereof.All such changes, modifications, variations and other uses andapplications which do not depart from the spirit and scope of theinvention are deemed to be covered by the invention which is limitedonly by the following claims.

1. A motor vehicle including a passenger compartment, comprising: a seaton which an occupant sits; a movable headrest associated with said seat;and a system for positioning said headrest adjacent a head of theoccupant in an impact involving the vehicle, said system comprising: ananticipatory crash sensor system arranged to produce an output signalwhen an external object is approaching a rear of the vehicle at avelocity above a predetermined velocity; a headrest movement systemarranged to move said headrest; and a sensor system arranged todetermine when said headrest contacts or is proximate the occupant'shead; whereby upon the determination of a pending rear impact betweenthe external object and the vehicle, said output signal is produced bysaid crash sensor system and said headrest is then moved into a positionin contact with or proximate the occupant's head as determined by saidsensor system prior to the impact of the occupant's head with saidheadrest.
 2. The vehicle of claim 1, wherein said headrest movementsystem is arranged to move said headrest from an initial position to aposition proximate to the occupant's head, and said sensor system isarranged to determine the location of the occupant's head relative tosaid headrest, further comprising a processor arranged to determine themotion required of said headrest to place said headrest proximate theoccupant's head, said processor providing said motion determination tosaid headrest movement system upon receipt of the output signal fromsaid crash sensor system, whereby upon the determination of a pendingrear impact between the external object and the vehicle, said outputsignal is produced by said crash sensor system and said headrest is thenmoved into a position adjacent the occupant's head prior to the impactof the occupant's head with said headrest.
 3. The vehicle of claim 2,wherein said sensor system comprises: transmitter means attached to saidheadrest for transmitting radiation to illuminate different portions ofthe occupant's head; receiver means attached to said headrest forreceiving a set of first signals representative of radiation reflectedfrom said different portions of the occupant's head, said receiver meansproviding a set of second signals representative of the distances fromsaid headrest to the nearest illuminated portion of the occupant's head;and computational means for determining the headrest vertical locationcorresponding to the nearest part of the occupant's head to saidheadrest from said set of second signals from said receiver means. 4.The vehicle of claim 2 wherein said sensor system is structured andarranged to be operable in the presence of objects which obscure theoccupant's head.
 5. The vehicle of claim 4, wherein said sensor systemcomprise: transmitter means for illuminating a selective portion of theoccupant and the head-obscuring objects in the vicinity of theoccupant's head; illumination sensor means for receiving illuminationreflected from the occupant and the head-obscuring objects, saidillumination sensor means providing a signal representative of thedistance from said illumination sensor means to said illuminated portionof the occupant and the head-obscuring objects; means for changing theselective portion of the occupant and the head-obscuring objects whichis illuminated by the illumination, and a processor comprising analgorithm for sequentially operating said selective portion changingmeans so as to illuminate different portions of the occupant and thehead-obscuring objects to thereby obtain a plurality of distancemeasurements from said illumination sensor means to the differentportions of the occupant and pattern recognition means for determiningthe location of the occupant's head from the plurality of distancemeasurements from said illumination sensor means to the differentportions of the occupant and the head-obscuring objects, wherein saidprocessor, using said pattern recognition means, determines the locationof the occupant's head.
 6. The vehicle of claim 5, wherein said patternrecognition means comprise a neural network.
 7. The vehicle of claim 1,wherein said head location sensor means are structured and arranged todetermine the location of the approximate longitudinal location of thehead from said headrest.
 8. The vehicle of claim 1, further comprisingat least one airbag, said sensor system being structured and arranged todetermine the location of the occupant's head relative to said at leastone airbag.
 9. The vehicle of claim 1, wherein said crash sensor systemcomprises an ultrasonic transducer or an electromagnetic wavetransducer.
 10. The vehicle of claim 1, wherein said crash sensor systemcomprises means for measuring the distance from the vehicle to theobject.
 11. The vehicle of claim 1, wherein said crash sensor systemcomprises means for recognizing a pattern of the object to therebyidentify the object.
 12. The vehicle of claim 1, wherein said sensorsystem includes a switch which is contacted by the occupant's head andthen causes said headrest movement system to stop movement of saidheadrest.
 13. The vehicle of claim 1, wherein said sensor systemincludes a proximity sensor which is arranged to detect when saidheadrest is proximate the occupant's head and then cause said headrestmovement system to stop movement of said headrest.
 14. The vehicle ofclaim 1, wherein said sensor system comprises a contact sensor arrangedin said headrest which is contacted by the occupant's head and thencauses said headrest movement system to stop movement of said headrest.15. The vehicle of claim 1, wherein said headrest comprises a frameattached to said seat, an airbag containing air in a pre-inflatedcondition, means for maintaining said airbag in the pre-inflatedcondition prior to an impact of said headrest against the occupant'shead, supporting structure attached to said frame containing saidpre-inflated airbag and having means for constraining the motion of saidpre-inflated airbag to a substantially fore and aft direction, and acover substantially surrounding said pre-inflated airbag, said coverelastically deformable in response to pressures from said pre-inflatedairbag, wherein when the occupant's head is impacted by said headrest,air within said pre-inflated airbag flows substantially within saidairbag to change the shape of said airbag so as to approximately conformto the head and neck of the occupant.
 16. The vehicle of claim 15,further comprising a flow restriction in said airbag to permit thecontrolled flow of air out of said airbag during the impact of saidheadrest against the occupant's head to thereby dampen the impact of theoccupant's head onto said headrest.
 17. A method for positioning aheadrest of a seat in a vehicle in anticipation of a rear impact intothe vehicle, comprising: determining the location of the head relativeto the headrest; determining when an object external of the vehicle isapproaching the rear of the vehicle at a velocity above a predeterminedvelocity which is indicative of a pending rear impact between the objectand the vehicle; and positioning the headrest adjacent a head of theoccupant when a determination is made that the object is approaching ata velocity above the predetermined velocity and the determined locationof the headrest is not adjacent the occupant's head.
 18. The method ofclaim 17, wherein the step of positioning the headrest comprises movingthe headrest until the headrest contacts or is proximate the occupant'shead.
 19. The method of claim 18, further comprising arranging a sensorin the headrest or seat to determine when the headrest contacts or isproximate the occupant's head.
 20. The method of claim 17, wherein theheadrest is positioned adjacent the occupant's head prior to the impact.